Simplify to lowest terms. $\dfrac{9}{30}$
Explanation: What is the greatest common factor (GCD) of 9 and 30? $9 = 3\cdot3$ $30 = 2\cdot3\cdot5$ $\mbox{GCD}(9, 30) = 3$ $\dfrac{9}{30} = \dfrac{3 \cdot 3}{ 10\cdot 3}$ $\hphantom{\dfrac{9}{30}} = \dfrac{3}{10} \cdot \dfrac{3}{3}$ $\hphantom{\dfrac{9}{30}} = \dfrac{3}{10} \cdot 1$ $\hphantom{\dfrac{9}{30}} = \dfrac{3}{10}$